On account of switching processes, load fluctuations of greater or lesser magnitude occur in integrated circuits (IC). By way of example, load fluctuations are brought about by the occasional activation or deactivation of partial regions or modules of an IC. Such connectable or disconnectable modules are being employed more and more in modern ICs since they enable a demand-oriented control of the power consumption of the IC. A module is activated only when it is currently needed. For the rest of the time, the module is in an operating state with low or no power consumption. The change between operating states is usually performed by disconnection of the supply voltage or by disconnection or reduction of the clock frequency of the module.
What is disadvantageous in this case is that the switching processes produce undesirable transients on the supply lines, which can have a disturbing effect on other chip components. The higher the number of switchable modules, the greater the difficulties to be expected. So-called “mixed signal” systems, which combine digital and analog assemblies on an IC, are particularly susceptible to the occurrence of transients.
In order to reduce the harmful influence of transients, it is already known to protect sensitive components of the chip from the transients by means of suitable shielding.